Liner package for hooks



Feb. 12, 1952 Q o RQBERSON 2,585,408

LINER PACKAGE FOR HOOKS I Filed Oct. 2. 1950 r: w 1 19 L i 11- 18 201 551,2 In I: 36

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ATTORNEYS Patented Feb. 12, 1952 UNITED STATES PATENT OFFICE 2,585,408LI ERPAoKAgn FOR HOOKS Claude McInnis Roberson, Shreveport, La.Application October 2, 1950-, Serial N 0. 188,031

They must be capable of supporting a rotary swivel and a drill stem,which may weigh as much as 600,000 pounds, or more. To replace the oldtype hook with one of the type disclosed in my above patent is anexpensive operation. Consequently, it is proposed to insert into anopening in such hooks an operating unit which will permit sensitivecontrol being obtained over the lifting force exerted on the hook, allowrotation of the hook shank relative to the operating mechanism, andpermit control of the operating mechanism from a remote position, all ata substantially smaller cost than that required for replacement of theexisting hook with my improved type of hook.

As well as being used to support the rotary swivel, the kelly and thedrill stem during the actual drilling operation, the hooks of rotaryrigs are also used to support and position stands of pipe which are tobe added to the drill stem as the drill bit penetrates deeper into theearth. A still further use of such hooks is to hold stands of pipe asthey are detached from the drill stem during replacement of the bit andto provide the necessary lifting force to the stand as the joint betweenthe lowermost section of pipe of the stand to be removed and theuppermost section of pipe of the drill stem left in the well isdisengaged. Particularly during this latter operation, the pulling forceexerted on the pipe stand by the hook must be held under close controlso that the threads of the tool joints which connect the sections of thepipe together will not be damaged during disconnection.

The hooks now generally in use do not satisfactorily provide thisnecessary close control. An oil well hook has been marketed which wasintended to supply this close control by the provision of hydrauliccontrol means for the wellknown spring hook. With this hook, the forceof the spring was released when the pipe stand was to be raised from thedrill stem, and the choke of the hydraulic means gave some control overthe speed of application of the upward.

spring thrust to the hook. However, if the speed of the disengagingaction on the threaded release or exertion of force often caused damageto the tool joints and other equipment, as well as being dangerous toworkmen, when such large apparatus as that used in drilling operationswas involved.

During the attachment of additional pipe stands to the drill stem anddetachment of sections of pipe from the stem, the stands and sectionsmust be rotated to engage and disengage the threaded connections. Thehook is directly supported by a travelling block through which cable,called the drilling line, is passed, the travelling block beingsuspended from a stationary crown block by the drilling line. If thehook body and travelling block are rotated with the hook, the drillingline will be twisted, causing snarling and possible damage to the line.Consequently, it is desirable that the hook be freely rotatable with thestand or section, but that the hook'body, which is directly attached tothe travelling block, be stationary relative thereto.

The hook liner package or unit of the present invention is so designedthat close control over the force exerted by the hook on the pipe standis possible and free rotation of the hook relative to the hook body mayoccur.

"The liner package or unit of the present invention is inserted into asubstantially cylindrical space in an existing hook. The unit has a Icylinder liner, the outer wall of which is positioned adjacent "theinner wall of the cylindrical space of the hook. Within the upperportion of the liner a partition extends across the liner and a pistonis positioned above the partition. The partition and the piston form theends of 4?)" an expansible fluid chamber, the upper portion of the hookshank, the piston rod and the connection between the two are enclosed bya cylindrical skirt extending downwardly from the liner cylinder. Thehook shank has an enlarged portion which rests against and is supportedby a bearing member rotatably supported on an inwardly-extendingshoulder formed on the lower end of the hook body, the cylindrical skirtextending downwardly to just above the bearing member, and preventingupward movement of the bearing member in the cylindrical space.

Supply of fluid under pressure to the expansible chamber formed withinthe cylinder liner causes an upward force to be exerted on the pistontending to move it upwardly. Since the piston is connected through itspiston rod to the hook shank, an upward force will also be exerted onclose control over the force or upward thrust ex-- erted on the pipestand by the hook when a pipe stand is to be disconnected or connectedto the drill stem and allows rotary movement of the hook with respect tothe piston and the piston rod. Furthermore, to provide for thesedesirable features, it is not necessary to replace the entire existinghook with new one. The existing hook may be used, the liner unit merelybeing inserted into the existing hook body.

The invention will be more fully described in connection with theaccompanying drawings which illustrate a preferred embodiment of theinvention.

In the drawings:

Fig. l is an elevational view of a hook embodying my invention, and

Fig. 2 is 9, vertical sectional view through the hook body of Fig. 1with my liner unit positioned therein, with the hook bail removed. 7

Hook assemblies for use in rotary drilling rigs comprise generally ahook I and a hook body 2. The hook, body has a pair of bail ears 3 atits upper end to which is attached a bail 3' to be supported from thetravelling block (not shown).

The hook body 2 has a substantially cylindrically-shaped chamber 4extending longitudinally therethrough. At the lower end of the chamber,the wall of the hook body extends inwardly to form a shoulder 5 uponwhich a bearing member 6 is supported. Ball bearings l are interposedbetween upper and lower bearing rings la and lb positioned between thelower surface of the bearing member 6 and the shoulder 5 at the lowerend of the hook body to allow rotation of the bearing member 6 relativeto the hook body 2.

The hook has a vertically-extending hook shank B threadedly or in othersuitable manner connected thereto and extending upwardly therefromthrough the lower entrance into the hook body 2. The bearing member hasan inwardlyextending flange 6' at its lower end which forms an annularbearing enclosing the hook shank. This annular bearing acts to preventlateral movement of the hook shank when the hook is rotated.

The hook shank 8 has an enlarged radiallyextending bearing portion 9*located within the lower section of the cylindrical chamber 4, the

4 lower surface of which rests upon the bearing member 6 when the hookshank is in its lowermost position, as hereinafter more fully described.

The hook liner package or unit comprises a oylindrically-shaped linerill, the upper portion H of which forms the wall of an expansible fluidchamber 12. The upper end of the chamber 4 is closed by a cap member I3,which has a plurality of vent holes l3 through it to permit escape ofair when the piston is moved upwardly. The cap member has an annularflange l4 adjacent the radial extremity of its under side which bearsagainst the, upper outwardly flanged end [5 of the cylinder liner. Thelower end of the expansible chamber I2 is defined by a radiallyextendingpartition l6 which is welded, or in other suitable manner attached, tothe lower end of the upper portion ll of the cylindrical liner. Acylindrical piston I7 is mounted in the fluid chamber l2 for.reciprocation by fluid pressure supplied to the expansible chamber, aswill be later explained. The piston H has sealing rings l8 inserted inslots in its peripheral edge portion which bear against the inner wallof the upper portion H of the cylindrical liner to prevent fluid escapefrom one side of the piston to the other.

The lower surface of the outwardly extending flange 15 formed at theupper end of the upper portion ll of the cylindrical liner lies againsta corresponding inwardly extending shoulder l9 formed at the upper endof the hook body.

The piston I! has an upwardly converging tapered bore 20 extending fromits lower side to a recess 2| formed in its upper side. The upper end ofthe. piston rod 22 has a correspondingly tapered portion which extendsthrough the tapered bore 20 and has a threaded surface into which athreaded nut or cap 23 is threaded to rigidly secure the piston to thepiston rod. The piston rod 22 is thereby arranged to move verticallywith the piston ll.

The piston rod 22 also extends through a central bore in the partition16, and appropriate packing 24 is inserted between the piston rod 22 andthe bore wall of the partition, the packing being held in-position by aplate 25 surrounding the piston rod 22 and bolted to the under side ofthe partition.

The lower end of the piston rod 22 terminates in a cap-portion 26 whichfits over the upper end 21 of the hook shank, above the radiallyextending bearing portion 9.

The hook shank 8 is rotatably connected to the piston rod 22 by ballbearings 28 positioned within opposed complementary slots formed in theinner surface of the cap portion 26 and the outer vertical surface ofthe upper end 21 of the hook shank.

A vertically extending cylindrical. skirt 29 is attached to the lowerend of the upper portion l I of the cylindrical liner. The skirt 29 isspaced slightly from the wall of the hook body 2 and surrounds thepiston rod 22, the connection between the piston rod and the hook shank8, and the radially-extending bearing portion 9 of the hook shank. Thelower end of the cylindrical skirt 29 is. spaced a short distance abovethe bearing member 6 to avoid abrasion between the skirt and the bearingmember when the bearingmember rotates relative to the hook body, but yetto prevent upward movement of the bearing member when the hook shankmoves upwardly.

The wall of the hook body 2 has a passage 3Q through the side thereoffor a fluid supply pipe 3| which conducts fluid from an external source(not shown) to the expansible chamber l2. The supply pipe 3| extendsthrough the passage 36 and has its inner end extending upwardlysubstantially at right angles and terminating within a valve body 32which is flxed within a bore as through the partition IS. A valve 34 ispositioned adjacent the outlet of the valve body 32 and urged by aspring 35 to closed position against its seat upon the upper surface ofthe valve body. The spring 35 is interposed between aninwardly-extending flange 35 of the valve body and a plate 31 fixed tothe lower end of a valve rod 38 connected to the lower surface of thevalve 34. Fluid under pressure entering through the supply pipe 3| tothe valve body 32 will press valve 34 off its seat, against the actionof spring 35, and allow the fluid to pass through the bore 33 in thepartition l6 into the expansible cham ber l2.

The valve 34 has orifices 39 therethrough which allow fluid within theexpansible chamber l2 to escape slowly through the orifices into thefluid supply pipe 3| when the fluid pressure is removed from the fluidsupply pipe, or when a heavy load is put on the hook. The slowness ofthis escape of fluid allows time for the heavy machines which move thetravelling block to get up to full speed before they take the load ofthe pipe supported by the hook. The orifices also provide a dashpotaction which prevents sudden thrust forces from being exerted on thebearing member.

In the operation of the hook, whenever it is desired to impart a liftingforce to the hook, air or other fluid under pressure is admitted throughthe fluid supply pipe 3| and the valve body 32 to the expansible chamberI2. The fluid thus admitted will exert pressure upon the piston l1tending to force it upwardly within the cylinder liner. Since the pistonis connected to the hook shank 8 by its piston rod 22, an upward forcewill also be exerted on the hook, tending to move it upwardly. The forceexerted on the book will be proportional to the pressure of the fluidwithin the expansible chamber l2. That pressure may be set to the propervalue, the value being determined by the weight which the hook must liftand the acceleration with which it is desired to move that Weightupwardly when a stand of the pipe is to be disconnected from the drillstem. Appropriate valve means (not shown) is provided to allow closecontrol over the fluid pressure, and the force exerted on the hook maybe kept within limits selected to insure that the threads of the tooljoints are not damaged during the disconnection. The valve is located ata convenient position remote from the hook, so that the operator neednot move with the hook.

When the threaded joint has been disengaged, the fluid pressure may beturned off and the piston permitted to return to its lower position, thefluid escaping from the expansible chamber through the orifices 39 inthe valve 34 into the fluid supply pipe 31. However, since the weightsupported by the hook is very large, it is desirable that the weight besupported by the hook body itself, rather than by the radial partition I6. Accordingly, the piston rod 22 is of sufflcient length that, duringdownward travel, the radially-extending bearing portion 9 of the hookshank will reach the upper surface of bearing member 6 while the lowersurface of the piston l1 is stillspaced a short distance from theparti-- tion l6. Since the piston I! never. rests upon the partition Hi,the partition is not required to support the weight of the hook and theapparatuswhich the hook carries.

During engagement and disengagement of one section of pipe from another,the hook, which supports the pipe, must be rotated because the pipejoints are threaded. If the piston rod rotated with the hook, thetorsional force exerted on the packing 24 would be transmitted to thepartition l6 tending to cause the cylinder liner and the hook body torotate with the hook. However, neither the piston rod nor the pistonwill be rotated because of the rotatable connection between the upperend of the hook shank and the cap portion at the lower end of the pistonrod.

Consequently, no torsional force is exerted on the upper portion of thecylinder liner tending to rotate the liner and the hook body. Twistingof the drilling line is thereby avoided. Furthermore, no unnecessarywear is put on the piston and the apparatus cooperating with it due torelative rotation between them.

Moreover, the bearing member 6, which rotates with the hook shank 8, isrotatable with respect to the hook body 2, so that the hook body remainsstationary while the hook rotates.

It is apparent that many minor changes can be made in the structureherein disclosed without sacrificing the advantages thereof or departingfrom the scope of the appended claims.

I claim:

1. An oil well hook assembly comprising a hook body whose walls form acylinder therein, a cylinder liner positioned within said cylinderhaving an outer portion in frictional engagement with the cylinder walland constrained against inward movement within the cylinder, a piston insaid outer portion, a partition extending across the outer portioninwardly of the piston, a piston rod secured to said piston andextending therefrom through the partition, sealing means between thepiston rod and the partition, the piston rod, the partition, and thesealing means defining one end, and the piston defining the oppositeend, of an expansible fluid chamber in the outer portion of the cylinderliner, means for admitting fluid under pressure to said expansiblechamber, a hook having a shank connected thereto with its distal portionextending into the cylinder, said shank having an enlarged portionwithin the cylinder, a bearing member rotatably supported on the wall ofthe cylinder for supporting said enlarged portion of the shank, the endof the shank inwardly of the enlarged portion having a peripheral slotformed thereon, the free end of the piston rod having a cap portionfitting over the inner end of the hook shank, said cap portion having aperipheral slot in its inner face complementary with the slot on saidend of the hook shank and bearings positioned in said complementaryslots to allow rotatable movement of the hook shank relative to thepiston rod, said cylinder liner also having a cylindrical skirtdepending from said outer portion thereof having its distal endpositioned adjacent said bearing member inwardly thereof to preventinward movement of said bearing member, whereby admission of fluid underpressure to said expansible chamber causes an upward force to be exertedon the hook. V

2. In an oil well hook assembly comprising a hook and a hook body havinga bore therein, said hook having a shank connected thereto with itsdistal portion positioned within said here in the hook body, a pistonrod secured to said piston and extending outwardly therefrom, saidpiston rod having a cap portion fitting over the distal portion of thehook shank, means for rotatably connecting the piston rod to the hookincluding bearings positioned in complementary slots formed on thedistal portion of the hook shank and the inner wall of the cap portionof the piston rod, means extending across said chamber and forming withsaid piston an expansible fluid chamber within said bore in the hookbody, and means for supplying fluid under pressure to said expansiblechamber to exert a lifting force on the hook.

CLAUDE McINNIS ROBERSON.

8 REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 642,742 Evans Feb. 6, 19001,591,671 Flanders July 6, 1925 1,825,018 Smith Sept. 29, 1931 1,905,065Scholl Apr. 25, 1933 1,995,836 Buckwalter Mar. 26, 1935 2,443,568 PalmJune 15, 1948 2,519,288 Roberson Aug. 15, 1950

